Electron Structure• The Quantum Number• The electron’s “hood”

Electron Structure• The Quantum Number• The electron’s “hood”• 3 dimensional address

Electron Structure• The Quantum Number• Attraction versus repulsion determines

region, shape of region and spin of electron• No electron can have the same 4 quantum

numbers (Pauli Exclusion Principle)

Electron Structure• The Quantum Number• Principal energy level (n)• 2 dimensional representation

Electron Structure• The Quantum Number• Principal energy level (n)• Real pattern far different- both wave and particle

• L number (azimuthal) – shape and orbital

Electron Structure• The Quantum Number• Magnetic or m number• Spatial orientation of the orbital within

atom• Starts with negative of l and goes to

positive• E.g. l=2, m=-2,-1,0,1,2

Electron Structure• The Quantum Number• Electron-spin quantum number • AKA magnetic (ms) number

• Illustration – Helium (He) atom• Two electrons in one cloud• Opposite “spin” or magnetic qualities• + ½ (Arrow up) or -1/2 (arrow down)

Electron Structure The Quantum Number n=1, l=0,

m=01s2

s=+½,-½   

Electron Structure This is the helium atom. It has 2 electrons. These are

able to share the same s orbital because of opposite spins. The "2" in "1s2" means there are 2 electrons in that orbital. "s" orbitals can only hold 2 electrons, so that's as high as you will ever see it. The 1 in "1s2" means this is the s orbital belonging to the n=1 shell. n=1, l=0, m=0

1s2, s=+½ , -½  

Electron Structure

• Pauli Exclusion Principle•Each orbital can contain only one electron with each kind of spin• If two electrons are in an orbital they must have different ms values

Electron Structure

Electron StructureDiagonal fill rule

◦s levels fill first, p next , d after p and f last of all

Electron StructureHund’s Rule

Electron StructureAufbau principle

Electron Configuration & The Periodic Table

Orbital Notation

Orbital NotationLonghand notation for Li:

1s2 2s1

Shorthand notation for Li: [He]2s1

Be: [He]2s2 B: [He]2s22p1

See table 4-5 p. 90Hund’s rule example: C

Atomic Number & Mass

Atomic Mass = sum of mass of protons + mass of

neutrons

Atomic Number & Mass

http://jefflittle.edu.glogster.com/the-periodic-table/

The Periodic Table

http://jefflittle.edu.glogster.com/the-periodic-table/